Alkyl aryl sulfonates



United States Pa ALKYL ARYL SULFONATES Robert W. F. Kreps, Jacobus .l. Tjepkema, and Pieter L. Kooijman, Amsterdam, Netherlands, assignors to Shell Development Company, New York, N. Y., a corporation of Delaware No Drawing. Application May 17, 1954, Serial No. 430,398

Claims priority, application N etheriands May 29, 1953 9 Claims. (Cl. 260501) This invention relates to surface-active alkyl-substituted aromatic sulfonic acids and salts thereof. a group of new compounds of this type having alkyl It deals with groups of a special structure which gives them improved detergent properties.

A variety of different alkyl aryl sulfonates have been suggested as detergents, wetting agents, dispersants and the like. Propylene tetramer benzene sulfonates and keryl benzene sulfonates are typical of the compounds which have gone into large scale use in these fields. The present invention provides a dilferent type of alkyl aryl sulfonate which has now been found to give exceptionally advantageous results in all these applications and especially as detergents, particularly for cleaning dishes,

ticularly desirable surface activity. Further objects and advantages of the invention will be apparent from the following description in which, for the sake of brevity, the alkyl aryl sulfonic acids and their salts will be referred to generically as alkyl aryl sulfonates.

The provision of heavily built dey The special class of novel alkyl aryl sulfonatesof the invention have the general formula wherein M represents hydrogen or a cation, Ar is an aryl hydrocarbon radical, especially a phenylene radical and R1,R2 and R3 are alkyl radicals which meet the following requirements:

(I) The total number of carbon atoms in the radical Ra is not less than 13 nor more than 16, and

(2) The number of carbon atoms in R1 is not more than twice the number in R2, while R3 contains at least one but not more than the same number of carbon atoms of the larger R1 and R2.

Especially useful are the alkyl benzene sulfonates of the foregoing formula in which the maximum difference between the number of carbon atoms in R1 and R2 is not more than two. It is also preferred to use compounds in which R1, R2 and R3 are straight chain, normal alkyl radicals.

Among the alkyl aryl sulfonates meeting these requirements, the following have been found to give advanta geous results: the sodium saltsof monosulfonation products of 6-methyl-6-phenyldodecane, 5-ethyl-5-phenylundecane, 6-ethyl-6-phenylundecane, 5-n-propyl-5-phenylundecane, 6-n-propyl-6-phenylundecane, S-butyl-S-phenyldecane, 6-ethy1-6-phenyltridecane, 6-n-propyl-6-phenyldodecane, S-n-butyl-S-phenylundecane, 6-butyl-6-p'henylundecane, 7 ethyl 7 phenyltetradecane, 7 n propyl- 7-phenyltridecane, and 6-butyl-6-phenyldodecane. Instead of these alkylbenzene sulfonates, the corresponding alkyl toluene and like derivatives can be used, but it has been found that the alkyl benzene compounds give superior results.

The new alkyl aryl sulfonates having the foregoing essential structure can be produced by sulfonating the corresponding alkyl aromatic hydrocarbons. These hydrocarbons are obtained by alkylating the. chosen aromatic hydrocarbon with alkylating agents having the required arrangement of carbon atoms. Suitable alkylating agents are, for instance, the tertiary alkyl halides and tertiary aliphatic alcohols of the general formula Rz-C-X Ra wherein X represents halogen, preferably chlorine or bromine, or a hydroxyl group, and R1, R2 and R3 are alkyl groups having the previously indicated numbers of carbon atoms. Tertiary olefins corresponding to these halides and alcohols, for example, the dehydrohalogenation and dehydration products thereof, are also advantageous alkylating agents. Especially suitable tertiary olefins are those of the formula wherein R4 is an alkyl radical having one less carbon atom than R1 in the previously indicated formulae, and R2 and R3 are alkyl radicals as above described. These alkylating agents can be synthesized from hydrocarbons,

for instance, lower hydrocarbons, by known methods. Using such agents, it is feasible to prepare alkyl aryl hydrocarbons of the required structure in a pure or substantially pure form. However, it is not necessary to use pure starting materials in large scale manufacture of the new compounds and, for reasons of economy, it may be desirable to employ starting mixtures which contain isomers and/ or homologues of specified compounds. Excellent results can be obtained with alkyl aryl sulfonates which contain at least 60%, on a molar basis, of sul fonates havingalkyl groups of the special structure characterizing the new compounds of the invention. Preferably not more than 25%, more preferably not more than 10%, of the alkyl aryl sulfonate molecules present should have a constitution different from that indicated above as essential. I I

The alkyl aryl hydrocarbon or mixture of hydrocarbons chosen as starting material can be sulfonated in various Ways. One particularly suitable method of sulfonation,

particularly when using oleum as the sulfonation agent,

is described and claimed in the cope-riding application of Melstromand Carlson, Serial No. 238,386, filed July 24, 1951, now U. S. Patent 2,676,185. Other methods known to be useful in the sulfonation of alkyl aromatic hydrocarbons can, however, be used.

While the invention embraces the new alkyl aryl sul- These salts can be obtained readily by bases. The alkali metal salts, especially the sodium and potassium salts, are particularly useful as are also the ammonium and amine salts. The mono-, diand triethanolamine salts are examples of amine salts which have been found to have special advantages. Alkalineearth metal salts can also be used.

For detergent use the new alkyl aryl sulfonate detergents are advantageously used in combination with socalled detergent builders. For this purpose inorganic salts are particularly suitable. Typical examples of suitable inorganic salts are sodium sulfate, sodium carbonate, sodium phosphates, for instance sodium pyrophosphate, more particularly sodium polyphosphates such as sodium trior tetra-polyphosphate, sodium tetrapyrophosphate and sodium hexametaphosphate and sodium silicates, for example, sodium metasilicate (NazO.SiO2), alkaline sodium silicate (NazO.2SiOz) and neutral sodium silicate (NazO.3SiOz). It is in many cases advantageous to add one or more phosphates and one or more silicates in combination.

If desired, the compositions according to the invention may also contain so-called washing promoters. As a rule, these are cellulose or starch derivatives. The sodium salt of carboxy methylcellulose has become particularly well-known.

Components which may also advantageously be added to the compositions according to the invention are bleaching agents, i. e. agents which have an oxidizing effect and/or the so-called optical bleaching agents, the effect of which is due to fluorescence. In particular, peroxygen compounds such as persulfates, perborates and percarbonates, for example, are suitable as chemical, i. e. oxidizing, bleaching agents.

The new compositions can also contain other surfaceactive agents besides the alkyl aryl sulfonates of the invention. Most preferably, these are of the anionic and/or nonionic type. Alkyl sulfonates and alkyl sulfate salts having alkyl chains of 8 to 20 carbon atoms are typical of the anionic surface-active agents which can be used as well as alkyl aryl sulfonates which do not have the advantageous structure of the new compounds. Polyethylene glycol ethers and esters are examples of suitable nonionic surface-active agents which can be advantageously used in the new compositions.

The proportions of the various components in the new detergent compositions can be varied. These compositions can be in solid form, as powders, beads, flakes, bars, cakes and the like, or can be liquid solutions or gels such as are used as so-called liquid soap. These forms are most suitable for storage, transportation and sale of the new compositions, but the invention also includes these compositions in more dilute solutions such as are useful for washing and similar purposes. Whatever the form of the compositions, the surface-active compounds present can be in the range of 3% to 75% by weight of the total solids, i. e. disregarding any liquids which may be present. In most cases, the content of surface-active compounds will, however, vary between 5% and 60% by weight of the total solids, particularly between and about 40% by weight. Preferably, the surface-active compounds are predominantly alkyl aryl sulfonatm having the unique structure of the new compounds of the invention and, most preferably, only the new alkyl aryl sulfonates are used. Very good results have been obtained with detergent compositions containing to 30% by weight, preferably to by weight, of the new alkyl benzene sulfonates as the sole surface-active components present.

Sodium phosphates are particularly advantageous in the new compositions when they are intended for use in aqueous solution. The amount which will be used in such cases will be influenced by the hardness of the water which will be employed in making up the solutions. As a rule, phosphates, preferably sodium tripolyphosphate and/orsodium pyrophosphate, are used in amounts about equal to about twice the weight of the surface-active compound or compounds present. Sodium silicates are less effected by the hardness of the water used. They are added in amounts from about 20% to about 50% by weight of the surface-active components. Sodium metasilicate, alkaline sodium silicate and neutral sodium silicate have been found to be suitable. As previously pointed out, there are advantages in using one or more phosphates in combination with one or more silicates. The ratio of phosphate to silicate can vary considerably.

When a washing promoter such, for example, as the sodium salt of carboxy methyl cellulose or the like is used, amounts preferably between about 5% and about 20%, especially about 10%, by weight of the surface-active compounds present are suitable.

Compositions consisting of the following proportions of solid components have been found to be particularly effective for use in aqueous solution:

20 parts by weight of the special alkyl aryl sulfonates of the invention (in the form of sodium salts) 20-40 parts by weight of sodium polyphosphate and/ or sodium pyrophosphate.

The compositions should preferably also contain: 4-10 parts by weight of sodium silicate (meta, alkaline or neutral silicate) and/or 1-4 parts by weight of the sodium salt of carboxy methylcel-lulose.

In many cases it is particularly advantageous to add also one or more bleaching agents, preferably: 5-15 parts by weight of sodium perborate, if desired, in

combination with approximately 0.01 part by weight of optical bleaching agent.

If desired, other constituents, for example, urea, may also be added to obtain particular effects. Although the alkyl aryl sulfonates to be employed according to the invention have a very good foaming effect, in some cases it may nevertheless be important to add an extra substance which has a foaming and/ or foam stabilizing effect. This is particularly the case with compositions intended (for domestic use. Suitable foam promoters and stabilizers are, for example, fatty acid amides of ethanol amines such as lauryl ethanolamide, or sulfone-substituted amides such as lauryl sulfolanyl amide and the like whose use, for such purposes, is claimed in copending application of Morris and Sawyer, Serial No. 219,504, filed April 5, 1951, now U. S. Patent No. 2,743,236, or the 1,2-alkanediols claimed as foam promoters in copending application of Wijga, Serial No. 240,449, filed August 4, 1951, now abandoned. Usually about 1 to 5 parts by weight of such additives are sufficient.

The following examples illustrate in more detail some of the compositions of the invention and show some of their advantages but are not limitative of the scope of the invention.

EXAMPLES A number of the new alkyl aryl sulfonates of the invention were employed in preparing compositions as indicated in the following tables:

Table I Mixture Number Percent sulfonate (sodium salt) 15 25 30 60 30 Percent sodium pyrophosphate 40 35 30 10 Percent sodium tripolyphosphate. ,50 Percent sodium silicate (neutral) 5 10 3 Percent sodium perborate '10 10 Percent earboxy methyleellulose (sodium salt) 2 4 2 6 3 Percent optical bleaching agent 1 0.01 0.01 0.01 0. 01 0. 01 Percent sodium sulfate 28 16 16 4 57 1 A commercial product marketed as Tinopal SP.

Table II Mixture Number Percent sulionate (sodium salt) 5 28. 5 50 30 25 Percent sodium pyrophosphate 5 1 40 Percent sodium tripolyphosphate. 10 10 Percent borax 5 Percent sodium silicate (neutral) Percent sodium carbonate Percent sodium perborate..-

Percent carboxy methylcellul Percent Sodium sulfate t. Perceiit alkyl phenol polyethylene on e 1 A commercial product marketed as Tinopal SP.

The alkyl aryl sulfonates used in preparing these compositions were the following typical compounds having alkyl groups of the structure required in the new detergents of the invention, as shown by the number of carbon atoms in groups R1, R2 and R3 of the previously mentioned general formula.

1 Predominant component in a mixture with minor amounts of isomers; all others substantially pure compounds.

All of these compositions gave excellent results in washing chinaware and fabrics and produced abundant stable foam.

Compositions were also prepared corresponding to mixture No. 10 of Table II using a number of alkyl aryl sulfonates having structures which do not meet the requirements for the new compounds of the invention. These sulfonates are characterized below by the number of carbon atoms in their groups R1, R and & according to the preceding general formula, except that a zero indicates a hydrogen atom in place of an alkyl group.

These compositions were tested in comparison with similar mixtures prepared with new alkyl benzene sulfonates of the invention. The test compares the relative foaming powder of detergents in the presence of a form of dirt, tallow, which has an especially strong anti-foaming power. The test was carried out with four liters of an aqueous solution of each of the detergents containing 0,05% by weight of alkyl aryl sulfonate dissolved in water having a hardness corresponding to 250 mg. of calcium carbonate per liter. Each solution was heated to 60 C. and stirred mechanically for 30 seconds to produce foam. Then, successive additions of 2 grams of tallow were made carefully so as to disperse the tallow without forming any new foam. These additions were continued until the foam disappeared entirely. The following table gives the results of this test and shows the marked s uperiority of the new alkyl benzene sulfonates of the invention over other types of alkyl aryl sulfonates.

Sodium Sulfonate According to the invention:

Excellent results are also obtained when using the new sodium sulfonates of 5-n-propyl-5-phenyldecane, of 6- ethyl-6-phenyldodecane, of 7-methyl-7-phenyl-tetradecane, or of 6-n-propyl-6-phenyldodecane instead of the new compounds indicated in the foregoing table.

It will thus be seen that the invention offers considerable advantage over prior alkyl aryl sulfonates, particularly with respect to its application in washing operations. Many variations can be made in the invention, however, since the new compounds are also effective as wetting agents, dispersants and emulsifiers as well as foaming agents. They can likewise be used in compositions containing biocidal compounds and can thus be employed for the control of harmful organisms. Still other changes can be made in the new compositions Without departing from the invention which is not restricted by any theory proposed in explanation of the improved results which are obtained nor by the details given by way of illustration in the foregoing examples.

We claim as our invention:

1. Alkyl aryl monosulfonates of the benzene series having the general formula wherein M represents a cation, Ar is a divalent aromatic hydrocarbon radical of the henzene series, and R1, R2 and R3 are alkyl radicals, the total number of carbon atoms in the alkyl group being at least 13 but not more than 16 carbon atoms, the number of carbon atoms in group R1 having the maximum number of carbon atoms of said three alkyl radicals being not more than twice the number in group R2, and group R3 containing at least one but not more than the number of carbon atoms in group R1.

2. An alkyl aryl monosulfonate according to claim 1 wherein M represents a hydrogen atom.

3. An alkyl aryl monosulfonate salt according to claim 1 wherein M represents an alkali metal.

4. An alkyl aryl monosulfonate salt according to claim 3 wherein M represents a sodium atom.

5. An alkyl aryl monosulfonate salt according to claim 1 wherein M represents an alkanolamine group.

6. An alkyl aryl monosulfonate salt according to claim 5 wherein M represents the ethanolamine group.

7. The water-soluble monoalkyl benzene monosulfona-te salts having directly linked to the benzene ring a tertiary alkyl group 7' containing 1 3 to 16 carbon atoms wherein the number of vcarbonatoms in group R1 having the maximum. number of carbon atoms of said three alkyl radicals is not greater than twice the number in group R2, and group R3 contains no more carbon atoms than group R1.

8. An alkyl benzene monosulfonate salt according to claim- 7 wherein the maximum difierence between the number of carbon atoms in groups R1 and R2 is two.

9. A sodium alkyl benzene monosulfonate salt in accordance with claim 8.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Schwartz and Perry: Surface Active Agents, p. 232 

1. ALKYL ARYL MONOSULFONATES OF THE BENZENE SERIES HAVING THE GENERAL FORMULA
 5. AN ALKYL ARYL MONOSULFONATE SALT ACCORDING TO CLAIM 1 WHEREIN M REPRESENTS ALKANOLAMINEGROUP. 